Best of the inbox: the missing plaintext part

Best of the inbox: the missing plaintext part
Framing: shipping HTML-only with no plaintext multipart is a quiet spam-score tax most affiliates never notice. The fixes:

🚀 Deliverability
— Multipart/alternative explainer — earned its spot for showing filters penalize a missing or auto-generated text part.
— Hand-written plaintext template — picked because a real text version (not stripped HTML) reads cleanly in Apple Watch and text clients.

🧪 Tests
— With/without-plaintext spam-score run — worth it: adding a proper text part shaved real points off SpamAssassin.

📥 Swipe
— The link-parity checklist — included because mismatched links between HTML and text versions also flag you.

Through-line: the part nobody sees still gets scored.
Saved you ~70 minutes of invisible deductions.